1. Field of the Invention
The present invention generally concerns wide area multimedia broadband telecommunications systems and services, particularly systems and services for homes, offices, outdoor and/or remote locations where telecommunication terminals are attached to a wire-or fiber-based telecommunications network via wireless links, thereby permitting users of the telecommunications terminals the ability to roam freely and obviating any requirement that a wired "telecommunications outlet" should be available.
The present invention particularly concerns the partitionment of wide area multimedia broadband telecommunications systems and services both (i) in the media--radio, free-space optical, or wire and fiber--over which communications traffic from point to point and from time to time transpires, and also (ii) in the system hardware, and among the system protocols, for handling this communications traffic (upon the various media). All partitionment is to the end of ensuring universal low-cost high-performance wide-area (tele)communications availability. In particular, the present invention will be seen to be concerned with how to connect the existing world communications "backbone" which is, in America circa 1997, based primarily on wire and optical fiber lines, to the typical subscriber household and office--the so-called "last mile" problem.
2. Description of the Prior Art
2.1 General Challenges Besetting Universal Communications Systems and Services
For the past several years, the telecommunications industry has witnessed an explosive growth in the demand for (1) non-voice types of services (driven by so called multimedia traffic, and suggestive of some unspecified combination of low and high speed data, voice, image, and video); and (2) service to non-stationary, mobile, end terminals. See D. Wright, Broadband: Business Services, Technologies, and Strategic Impact, Artech House, Boston, 1993; A. S. Acampora, An Introduction to Broadband Networks, Plenum Press, New York, 1994; IEEE Communications Magazine, issue on Introducing the Internet Technology Series, Vol. 35, No. 1, January. 1997; T. S. Rappaport, Wireless Communications Principles and Practice, Prentice Hall, N.J., 1996; and IEEE Personal Communications, issue on Wireless ATM, Vol. 3, No. 4, August. 1996.
Despite this demand, three primary technical problems remain to be solved before a communications infrastructure adequate to meet modern demand can be created.
The first of these problems involves the inadequate capacity afforded by the copper wires which typically presently, circa 1997, serve to connect homes and offices to core, or "end-office", switches within the existing U.S. national telecommunications network. These wires are additionally characterized by their inflexibility to accommodate new and added communications devices at the user portal; exactly where changes are most likely to occur. In other words, even if all the copper wire in the U.S. was to be instantaneously converted to high-bandwidth fiber optics, the locations, and the physical connections, of new telephones or computers or televisions or other devices to the wire and fiber communications network would remain troublesome, effectively mandating extensive and expensive manual services to "wire" and "re-wire" the home or office site every time site service requirements change appreciably.
It would obviously be useful if some "magic box" existed in the attic, or the communications closet, which permitted that any communications device brought within the home or building, whether permanently or temporarily, could be immediately wirelessly integrated into the communications network totally without the use of skilled labor. The "magic box" would preferably be universal, inexpensive, and supportive of a high communications capacity. Although this "magic box" might occasionally have to be upgraded if new and very large communications requirements were to arise at the home or office site, the requirement of expensively "custom wiring" the communications of the home or office would be obviated.
The second problem concerns the limited available bandwidth of the radio spectrum to meet the demand for non-stationary and/or flexible communications services. The "black box" of the previous section could clearly be a cellular radio transceiver serving to link diverse communications devices, whether portable or not, to a communications grid by radio. Alas, the radio spectrum that is both now (i.e., in 1997) allocated, and reasonably allocatable, for general telecommunications services is already crowded, and incapable of meeting all the demands for real-time multimedia communication arising over any extended populated geographical area.
The third problem concerns the desire, if not the political necessity, of guaranteeing universally (i) available and (ii) affordable communications services. It is clearly possible to auction the radio spectrum, and to let those who can afford more use more. It is clearly possible to cost-effectively service certain metropolitan areas while leaving communication "backwaters" that are not fully enfranchised with evolving equipments and services. However, in a democracy there are limits in allocating the God-given public resource of the radio spectrum purely on financial grounds.
At the same time the existing U.S. national communications infrastructure presents challenges to future upgrading, it also presents opportunity. As reported by author and futurist George Gilder in his book "Into the Fibersphere", and in his columns of the "Telecosm Series" appearing in Forbes Magazine, "the ultimate source of bandwidth expansion is the immense capacity of optical fiber. Now comprising a global installed base of 40 million miles (25 million miles in North America), each optical fiber, as Paul Green of IBM estimated to Forbes ASAP four years ago [i.e., in 1992] commands and intrinsic available bandwidth of 25,000 gigahertz." How much bandwidth is this? It is more than all the radio telecommunications--from ultra low frequency communication with submarines to K band satellite links--that are at any one time transpiring on the entire planet. Yes, each single strand of 40 million miles of optic fiber already existing can potentially handle all the radio traffic in the entire world.
Where then exactly is located this wonderful pipeline to all the world's information? In America it is close by, but has not yet reached the average American doorstep. Five years ago each American household was an average of 1,000 households away from a fiber node, now it is but 100. At the beginning of 1996 15% of U.S. cable TV subscribers directly connected to fiber optics; at the end of 1996, 30%. Being that not all American households presently have, or even can have, cable television, the average separation in feet of a U.S. household or business from an optic fiber is still several hundred feet. And, due to the first problem discussed above, many Americans in metropolitan areas literally have optic fiber "at their feet" but are unable to effectively connect to it.
It will be seen to be the objective of the present invention to solve all three problems, and to cost-effectively and equitably avail all the world's peoples of the opportunity to communicate into the growing fiber optic communications "backbone" of the United States and of the world.
The capacity and flexibility problem at the user interface will be, by and large, solved by the present invention. The user will be able to add new telecommunications devices at will within broad limits. Although these devices will often be bi-directionally communicating, and are in general used for purposes such as Internet access, pay-per-view, programming on demand, and multimedia communication that are quite different from traditional broadcast radio and television, they will require no more "installation" than, for example, does a store-purchased radio or television receiving broadcast signals.
The limited available bandwidth of the radio spectrum will likewise seen to be solved--without repealing physical laws--by the expedient of reusing most portions of the radio spectrum.
Finally, the (i) availability and (ii) affordability of universal communications services will also be seen to be dealt with effectively in the present invention, where any system user is but little burdened with the cost of the communications network if he or she is but a light user of its services. The un-subsidized cost of, for example, "life line" telecommunications services, even in remote areas, should be commensurate with what it is now. This is true even though an immediate "next" user who is adjacently located both geographically and logically in the communications network may volitionally use awesomely large telecommunications services, incurring the costs therefore.